PANONYCHUS CITRI (ACARI, TETRANYCHIDAE) ON ORNAMENTAL SKIMMIA IN OREGON, WITH ASSESSMENT OF PREDATION BY NATIVE PHYTOSEIID MITES

In the U.S., Panonychus citri (McGregor) (citrus red mite) typically o ccurs on citrus in semi-tropical regions of California, Texas, and Flo rida. Its occurrence in the Willamette Valley, Oregon and its associat ion with an ornamental host plant Skimmia japonica Thunberg are report ed. To assess potential biological control of this pest, excess amount s of P. citri from S. japonica were provided to confined native predac eous phytoseiid mites of several species, including Amblyseius anderso ni Chant, Metaseiulus occidentalis (Nesbitt), Neoseiulus fallacis (Gar man), and Typhlodromus pyri Scheuten. Neoseiulus fallacis was also pre sented either with no food or with Tetranychus urticae (Koch) for comp arison with P. citri. Survivorship, activity, cumulative oviposition p er female per d, and cumulative immature production of the predaceous mites were assessed every 24 hours for seven days. Survival and ovipos ition by adult females and production of immatures by N. fallacis were higher with T. urticae vs. P. citri, but activity of adult females an d survival of immatures were about the same with either prey. All meas ured attributes of N. fallacis were at lower levels without prey than with P. citri, except activity (greater). Adult females of T. pyri, M. occidentalis and N. fallacis demonstrated greater survival and ovipos ition rates than did adult females of A. andersoni. When with P. citri , M. occidentalis and N. fallacis had greater survival of immatures th an did T. pyri or A. andersoni. When introduced to the host plant S. j aponica; N. fallacis significantly reduced the densities of P. citri i n five weeks when compared to pest mite populations lacking the predat or.